Temperature Sensor Normal Then Max

[Guest alexporter]

55 Citroen C3 1.4 Desire

 

Hi All,

I've done a search and found some people have had a similar problem to my girlfriend but no one's said if they were able to fix it.

 

Basically, the engine warms up normally and gets to 3 bars and then all of a sudden it starts bleeping and the bars go up to the max, 10 seconds or so later it drops back down to normal.

 

She says its happening most days but I've only ever had it happen to me when I doodling around town or stuck in traffic(like last night on the A12). When I'm stuck in traffice it will keep doing it every few minutes. I've heard the fan going when she's arrived home from work but not while I'm driving it.

 

 

From my research I believe it's one of the following:-

A)high temperature switch (aka thermostat?)

b)temperature sensor for the dash gauge

c)cooling fan

 

After doing my first google search on the problem I purchased a "c3 thermostat" which I think is the wrong part as I cant see it any where on the engine. C3 Thermostat. What I have found under the bonnet is something that looks like this

 

Anyways,

Can anyone tell me if I'm correct in thinking that the blue box is the sensor for the dash gauge and the red box is the high temperature switch? And if so do you have know which one is causing the problem. If these arent the sensors can you tell me where they are using this picture .

 

Many thanks

Alex

 

apolopgies for the large picture

http://www.tendringvolleyball.com/alex/IMG_0010%20%28Large%29.JPG

[paul.h]

If it is the 1.4 petrol, the red box is the GREEN 2 wire temperature sensor that operates the gauge. The high temperature sensor is down the side of the head, below and a bit behind the red box, this sensor is coloured BLUE (from memory) and has a single wire connector and to access it properly you need to remove the air filter box. Both sensors give a high temperature alarm and should operate the engine fan (via the management system).

 

You can see the thermostat at the bottom of your picture, it is part of the pipework, being the black plastic elbow with a jubilee clip to the radiator top hose, and has a built in wax type thermostat. Maybe have a look on eurocarparts to see what it looks like.

 

If buying sensors, you may be better getting them from Citroen using the car vin to make sure you get the right ones, since they are not much different to the ebay price on your link and there will not be any postage. Note the one on ebay says it is the blue coloured sensor so may be the high temp one and not the gauge one. One problem with an ebay link is that since it has gone past the sell time, your first link does not work.

 

If it is a sensor problem, the gauge one probably will give between 3 and max bars (by running the cabin heater to control the temperature - but this could also be a thermostat problem) but the high temp one is max bars or nothing since it simply earths the connector wire (could be a wire fault to this). I would have a look through the bumper to see if the radiator/air con condenser is blocked with debris/flies.

 

I have still not bothered to sort the high temp problem on our car since it has only happened twice in 3 years but I have a thermostat and temp sensor ready to fit.

[Guest alexporter]

Hi Paul,

Thanks for your quick reply.

 

I've changed the pictures on my previous post :-) I didnt see the bit about it being blue, I was just looking for a picture of what I thought I was looking at. Its the same as the other one just its got a screw thread on it.

 

Yes its a 1.4 petrol model and I've checked the rad out and its all clear of debris. When it goes up to the max its only there for 10 seconds max, turning the heater on has no effect. Am I right in my thinking that it sounds like its probably the thermastate then? Are they easy to fit?

 

Thanks

Alex

 

 

PS any idea what is in the blue box, as its only got one wire going to it and its attached to the

[paul.h]

The part in the blue box - there is not one on our car 2003 1.4sx petrol but the green/yellow earth wire is there. It may be a capacitor somebody has installed to overcome radio interference, this was common over 20 years ago.

 

As for the high temperature, it could still be either of the sensors or the thermostat. To change any of these needs the coolant partly draining so if money is not a problem it would be tempting to replace them all together or at least the thermostat (2 bolts and a jubilee clip) since out of these, this part could cause actual overheating provided the others are switching the engine fan on. If the gauge sensor is giving wrong values it could also have an effect on engine performance. The anti freeze is a type that does not need changing (possibly organic acid type OAT) so if you do not manage to save all the existing anti freeze when draining, you should use the same type to top up the level.

 

I would get a Haynes manual for your car if you do not have one, it will explain draining and filling the anti freeze to aviod air locks. Your local library may also have one plus usual shopping sources. If you are ok at French or use a dictionary, there is a good RTA manual which Amazon's French site have.

[iannez]

Think you will find the fan has seized or gone open circuit. never had to fit a thermostat to one of these but its in the black plastic housing under the blue plug and is held in with 2 10mm bolts. could be temp sensor (green 2 way plug) but these usually cause running probs. The part in the blue box is a capacitor and has nothing to do with cooling system. They were an after fit on early models and fitted as standard to sort running probs from around 2004 onwards so yours will have just missed it paul. there spliced into the wire from pin 4 from the coil multi plug if you ever need to fit one mate.

Is the fan running when temp gauge is in the red.